Oracle Migration Workbench --> HELP

Has anyone used Oracle Migration Workbench?
I have a problem with it.
want to move Informix to oracle.
it has an option to create a source model load... (OFFLINE or ONLINE).
I want to try to use OFFLINE... but I get an error (NO SOURCE METADATA
FILE WERE FOUND).
what kind of a metadata does it need?
I used export files and copy 0 of informix...but nothing works...
:-(*